Submersible salvage unit and method of operation



United States Patent [72] Inventors Frederick A. Kriedt Primary Examiner-Andrew H. Farrell 1722 East West Highway, Silver Spring, Attorne -Cushman, Darby and Cushman Maryland 20910; Thomas H. Sundstrom, 9706 Wicollet Ave. Rf g? r ABSTRACT: A submersible salvage unit is provided with a 48066 a n o support frame which carries opposed pairs of downwardly de- 21 A I N 5; pending arms for grasping a sunken vessel or other object. The w 0 1968 arms can be actuated from grasping to inoperative positions d 1970 by relative vertical movements of pontoons which are also car- 1 a an e ried by the support frame of the unit. The relative movements are effected by movement of either the pontoons or the sup- [54] SUBMERSIBLE SALVAGE UNIT AND METHOD OF port frame relative to the other. Buoyancy compensators are OPERATION provided in the salvage unit to ad ust buoyancies to match Claims, 19 Drawing Figs I loads which are to be l fted, and the buoyancy compensators include means for rapidly releasing buoyancy gas from the [52] U.S. Cl. 114/52 pontoons, if necessary. Also, buoyancy compensators on op- [511 B63: 7/08 posite sides of the salvage unit may include stabilizers which [50] Field ofsefll'ch -1 14/50, 51, relate h compensate to each other in their operations to 52 maintain stable attitudes of the salvage unit when it is lifting a load. A method of operation provides for an alignment and [56] References Cited sinking of the salvage unit over a sunken vessel, and engage- UNITED STATES PATENTS ment of the vessel is accomplished by adjusting buoyancies of v l,85l,892 3/1932 Bontempi 114/52 the entire salvage unit.

Patented Nov. 24, 1970 ATTORNEYS Patented Nov. 24, 1970 3,541,986

Sheet 2 of '6 ATTORNEYS INVENTORS Sheet I Patented Nov. 24, 1970 Patented Nov. 24, 1970 3,541,986

Shee 4 of 6 2 zosfifi INVENTORS FREDfK/Cfiflfl /ED r THO/VH5 A sum rem 79/ CA /6W0 K0 BY I ATTO EYS Pateilted Nov. 24, 1970 Sheet 5 of 6 'IIIIIIII'II'I'IIIIL ATTORNEYS Patented Nov. 24, 1970 3,541,986

Sheet 6 of6 \zy/j 327 /2 19/6;

m6 0 w 4 C)- we ATTORNEYS 1 SUBMERSIBLE SALVAGE UNIT AND METHOD OF OPERATION BACKGROUND AND BRIEF DESCRIPTION OF INVENTION This invention relates to the art of salvaging sunken vessels, or other objects, from a body of water, and in particular, the invention is concerned with improvements in salvaging units and methods of operation for retrieving sunken vessels from deep water. 7 v i It is known in the prior art to provide for various structures and devices which function to assist in the salvage of sunken vessels. Prior art arrangements have provided for an attachment of buoyancy tanks to sunken vessels, and various attempts have been made to design salvage rigs which can .embrace and lift a sunken object. For example, Buell US. Pat. No. 1,616,410 and. Powell US. Pat. No. 1,691,738 each describe designs for rigs which are intendedto be lowered into engagement with a sunken vessel for grasping and lifting the same. In the Buell arrangement, grasping arms are actuated by a number of lines which must be manipulated from the surface, and Powell discloses a design for actuating grasping arms by adjusting the buoyancy of tanks which are rigidly connected to the grasping arms. Other known prior art on this subject includes US. Pat. Nos. 1,415,533; 1,807,361; 1,854,026; 1,851,892; and 2,280,547.

Although various designs and assemblies have been attempted in the past, it has been our'experiencethat prior designs and assemblies have not solved the special problems of salvaging relatively large sunken vessels from deep water. It can be appreciated that the grasping and floating of a sunken vessel can be quite dangerous, and extremely un'stable conditions can arise while the vessel is beinglifted from its sunken position to the surface of a body of water. Actual salvaging operations in the past have involved substantial dangers to all personnel involved, and.much effortcan be lost and wasted if a vessel is lost from a salvaging rig during the floating or surfacing operations. Accordingly, the present invention is concerned with problems of a safeand controlled handling of relatively large objects which must be received and lifted to the surface of a body of water by a submersible salvage unit. The improvements of the presentinvention provide for greater safety and control of the entire operation so that sunken vessels can be retrieved relatively safely and at costs which are acceptable to present day requirements.

The salvaging unit of the present invention is of the type which can be floated to the location ofa sunken vessel so as to be sunk over the vessel for grasping the same and lifting it to the surface of a body of water. The salvage unit includes a support frame means which has sufficient length and width to position two rows ofgrasping arms over and around a vessel which is to be lifted. The support frame means provides rigidity and strength to the entire salvageunit, and buoyancy tanks are included in the structure of the support frame means for assisting in an adjustment of buoyancy conditions for receiving, releasing and handlinga load/A plurality ofgrasping arms are carried within the support frame means so as to define two rows of downwardly depending arm'members having inwardly projecting end portions at. their lowermost ends. The arm members are connected to the support frames so as to be actuatable from an inoperative position where the two rows of arms are spread away from each other to an operative, grasping position where the two rows of arms are moved towards each other and towards a central space defined within the confines of the salvage unit. Thus, opposed arms can be moved away from each other for placing the salvage unit over a sunken vessel, and then, the arms can be moved towards each other to grasp and retain thevessel for a subsequent floating of the combined unit and vessel to the surface ofa body of water. The present invention provides for a unique actuation of the grasping arms by means of pontoons which are carefully controlled in their relationship to the operation of the grasping arms. Pontoon means, which may be inthe form of a plurality of pontoons positioned along each side of the salvage unit, can be lifted and lowered on track structures associated with downwardly depending leg members of the salvage unit support frame. Lifting and lowering movements of the pontoons function to actuate the positions of the grasping arms, and the pontoons are linked to the grasping arms so as to transmit the controlled movements of the pontoons to desired movements of the grasping arms. A pontoon means on one side of the salvage unit controls grasping arms on an opposite side of the unit so that maximum leverage is obtained in the inward important because it permits an adjustment of draft of the entire salvage unit and a retained vessel once it has reached the surface without any danger of losing the vessel.

The invention also provides for novel buoyancy compensator devices associated with the pontoons, or other buoyancy tanks, which permit a careful regulation of buoyancy conditions for the entire salvage unit. The buoyancy compensators comprise tubular members which provide a communication between a sealed interior of the pontoons, or of separate compartments within a given pontoon, with an outside environment (thesea) so that controlled amounts of water can be admitted into pontoons to adjust buoyancy. Means are provided for adjusting the distance at which the lowermost end-of each buoyancy compensator extends into the interior space of a pontoon, and the tubular members of the compensators may include telescoping sections to permit such an adjustment. Also, means are provided forrapidly venting buoyancy gas from the pontoons with the buoyancy compensators so that extremely unstable attitudes can be avoidedduring a salvaging operation. Finally, a'novel arrangement is provided by stabilizer valving means associated with the buoyancy compensators to balance opposed pontoons on opposite sides of the salvage unit.

and sinking the unit into an embracing position over the sunken vessel after adjusting positive buoyancy capabilities of the salvageunit to substantially match the calculated, or known, weight of the sunken vessel. In the context of the present invention, the capabilities of the pontoons are adjusted and set by the novel arrangement of compensators associated with the pontoons, and a careful matching of buoyancy of all pontoons with the weight of a sunken vessel permits a controlled lifting of the combined weights of the salvage unit and the vessel by adjusting positive buoyancy of additional buoyancy tanks associated with a support frame structure of such a unit.

The salvage unit of the present invention permits a safe and controlled handling of sunken vessels without unreasonable or uneconomical requirements for additional devices or impossible control functions to be carried on by surface support personnel. These and other features and advantages of the present invention will become apparent in the more detailed discussion which follows, and in that discussion, reference will be made to accompanying the drawings as described below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational schematic view of the salvage unit of this invention being floated into an aligned position with a sunken vessel;

FIG. 2 is an end elevational view of the salvage unit, showing its grasping arms in outwardly extended positions for receiving a sunken vessel;

FIG. 3 is an end elevational view, similar to FIG. 2 showing the grasping arms in closed positions for retaining and lifting a sunken vessel;

FIG. 4 is a top plan view of the salvage unit;

FIG. 5 is a partial perspective view, schematically illustrating relationships of elements in the salvage unit assembly;

FIG. 6 is a top plan view of a pontoon means associated with one side of the salvage unit;

FIG. 7 is a detailed elevational view ofa single grasping arm means associated with the salvage unit;

FIG. 8 is a detailed elevational view, partially in cross section, of a jetting device associated with the arm means of the unit;

FIG. 9 is an end elevational view ofa leg member associated with the support frame structure of the'unit;

FIG. 10 is a detailed elevational view of a buoyancy compensator associated with the pontoon means, partially in cross section;

FIG. 11 is a cross-sectional view taken at lines 11-11 of the buoyancy compensator of FIG. 10;

FIG. 12 is a top plan view of structure associated with a stabilizer valve means carried at a lowermost end of the buoyancy compensator of FIG. 10;

FIG. 13 is a detailed top plan view of a valve means of the type shown in FIG. 12;

FIG. 14 is a schematic view illustrating the relationship between opposed buoyancy compensators, and their associated stabilizer valve means, for maintaining a balance between oppositesides of the salvage unit;

FIG. 15 is a schematic elevational view of a flexible pad means associated .with the arm means, for engaging and holding a sunken vessel in place relative to the arm means;

FIG. 16 is a view similar to FIG. 15, showing a variation in the arrangement ofFIG. 15;

FIG. 17 is an elevational side view of the flexible pad means illustrated in FIG. 16;

FIG. 18 is a top plan view ofa piping diagram for the salvage unit, showing a plan for controlling admission of air to various parts of the unit; and 1 FIG. 19 is a view of a guiding system associated with the salvage unit for alining the unit with buoys marking a sunken vessel or object.

DETAILED DESCRIPTION OF INVENTION FIG. 1 illustrates the salvage unit ofthe present invention in its environment of intended use. The salvage unit comprises a complete rig which can be floated and towed to the location of a sunken vessel, and-then, the unit can be aligned and sunk into a position over the vessel for receiving and retaining the vessel within opposed grasping arms associated with the unit. The salvage unit can be of any size and configuration, but it should be of sufficient dimensions to fully embrace and include whatever sunken vessel, or other object, is to be received within the grasp 'of its opposed arms. The particular constructional features and relationships which are offered by the present invention permitthe use of such a very large salvage unit in operations which are controlled, safe and economical for many present day salvaging requirements Also, the provisions of this invention for careful control and balancing of buoyancy factors of the salvage unit permit the unit to be safely used in deep water operations where special problems of pressure, floatation, and remote control arise. The operation and use of the salvage unit, as depicted in FIG. I, will be discussed in greater detail later.

FIGS. 2 through 6 show elevational and plan views of the unit and of components making up the salvage unit of the present invention. The salvage unit includes a support frame structure 10 which functions to provide strength and support to the entire unit and to components which are a working part of the unit. It is important that a salvage unit, of the size contemplated by this invention, maintain its integrity while being floated and towed as well as during actual salvage operations;

and the. structural relationships offered by this invention provide for a strong unit that has a capability of embracing a complete vessel and all its superstructure and which will hold together while being operated at sea. The support frame means 10 has an upper level structure 12 which is constructed in the form of compartmented tanks (as shown in FIG. 4) for providing a certain amount of buoyancy control to the entire unit, and it can be seen that the upper tank structures 12 are of means 16 may comprise any known mounting pin carried by each arm means 14 and received into reinforced structure as sociated with the upper level structure of the support frame 10. As illustrated in FIG. 4, the pivotal mounting points of opposed arm means, of each pair of arms. are offset from one another so as to provide a preferred alignment of lower portions of the individual arms with side wall portions of a sunken vessel. Also, offset pivotal connections provide for a stronger mounting of all arms in the support frame structure of the unit. Thus, each arm has its own hinged mounting relative to the support frame, and this provides a stronger structure than would be possible with a single hinging means being common to more than one arm. Although the illustrated embodiment of FIG. 4 shows a use of four pairs of opposed arms, it is to be understood that other numbers of arms may be utilized in any given structure.

The arm means 14 function as grasping arms for engaging and retaining a sunken vessel within the confines of a space defined between two rows of depending lower portions of such arms. Each arm has a general configuration as shown in FIG. 7, and each arm includes a downwardly depending portion 18, a lowermost projection 20 for placement beneath a sunken vessel, and an upper level portion 22 which functions as a lever for rocking the entire arm about its pivotal connection at 16. Considering a single pair of opposed arms, it can be seen that the depending portions 18 of each arm extend downwardly on opposite sides of the salvage unit, and the upper portions 22 of the opposed arms extend past each other from opposite sides of the salvage unit so that each arm is actuated from a side of the unit which is opposite to the position of its depending portion 18. This arrangement provides for maximum leverage and for a better control of the rocking movements of individual arms about their pivotal connections 16. Furthermore, this arrangement provides for a positive control of arm movements by adjusting buoyancy conditions for the entire unit, and without a necessary requirement for collateral driving mechanisms. An end view of opposite pairs of arms having upper level portions 22 bypassing each other can be seen in FIGS. 2 and 3, and a top plan view of the same relationship is shown in FIG. 4. FIG. 5 illustrates a configuration for the upper support frame 10 so that opposed pairs of arms can be rocked about their pivotal connections to the compartmented tank structure of the upper support frame.

One of the difficulties in prior art designs for salvage units of the type which are intended to grasp and retain sunken vessels has been a lack of control in effecting actual movements of grasping arms, or other grappling devices, and this problem has been compounded by a lack of control in maintaining a stable attitude of a sunken vessel once it is received into a salvage rig. Furthermore, prior designs have not provided for an easy release of a vessel once the vessel is surfaced or if unstable conditions are encountered during a lifting operation. The present invention provides for improvements in controlling the movement of the grasping arms 14, discussed above, and in addition, a better control is provided for maintaining a stable and upright attitude of the combined salvage unit and a retained vessel once the vessel is being lifted towards the surface of a body of water. As shown in FIGS. 3 and 4 the outermost ends of the upper portions 22 of each arm means l4 are linked to pontoon means 24. The linking connection is'indicated generally at 26, and, in one embodiment, the linkage may comprise a hydraulically actuated ram, of known construction, for effecting an adjustment of thelength of the linkage between the pontoon means 24 and their associated grasping arms22. Alternatively, the linking means 26 may comprise flexible or telescoping elements, and known jacking devices may be connected to the pontoon means 24 to provide movement of the pontoon means relative to the sup port frame 10. The pontoon means 24 may comprise one or more sealed tanks or pontoons (which may be compartmented) positioned on opposite sides of the salvage unit and carried on depending leg members 28 associated with the support frame structure 10. By carrying the pontoon means 24 on fixed structure associated with the support frame means 10, it is possible to obtain a carefully controlled and guided movement of the pontoon means 24 relative to the support frame and relative to any sunken vessel retained within the confines of the salvage unit. FIG. 4 illustrates a top plan view of two pontoon means placed on opposite sides of the salvage unit, and each pontoon means is constructed as a compartmerited tank which'is sufficiently airtight between adjoining compartments to permit a control of buoyancy of each compartment of each pontoon means. Alternatively, separate pontoons can be associated with each of the arm means 14, but the preferred arrangement isshown in FIG. 4. FIG. 6 further illustrates the pontoon means 24 for one side only of a salvage unit. Each pontoon means 24 includes rigidly affixed support structures for carrying the pontoon means 24 on a plurality of depending legs 28 associated with the'support frame 10. Each structure 30 may be in the form of a sleeve or collar which completely encloses whatever cross-sectional configuration is provided for a depending leg 28, and each leg 28 may be provided with tracks or rails for permitting a sliding engagement of the structure 30 therewith. Additional structures v I and devices, as are well known for jacking drilling platforms and other seagoing structures on columns, may be included to provide a smooth movement of each pontoon means 24 up and down a plurality of depending legs 28, and rollers or other bearing means may be used to obtain a smooth movement between the pontoon and the support frame.

When all of the structures which have been discussed so far are assembled, it can be seen that there is provided a relatively rigid support frame 10 having two parallel rows of depending legs 28. Pontoon means 24 are carried for'sliding movements up and down-the two parallel rows of depending legs 28,'and the movements of the pontoon means 24 (or of the support frame relative to the pontoons) are transmitted to'corresponding movements of upper arm portions 22 which are linked to the pontoon means. Each upper arm portion 22 transmits its movements to a downwardly depending arm portion 18 by rocking the entire arm about its pivotal connection to the support frame 10, and this movement is used to effect an opening and closing of opposed rows of depending arms carried within the confines of the support frame 10. Thus, opposite rows of arm means 14 can be spread away from each other to receive -a sunken vessel (or to discharge the same once it is floated),

and the opposite rows of arms can be moved towards each other by adjusting the buoyancy of the pontoon means 24 or of the frame 10 so as to move the pontoon means relative to the support frame 10 from which they are carried.

FIG.8 illustrates additional features and details of structurcs associated with the arm means 14. At the lowermost end of each arm means (or of selected arms of a given unit), devices may be provided to assist in the insertion of the lowermost end 20 underneath a sunken vessel. Generally, the submersible salvage unit of this invention will operate in areas where the sea bottom is relatively soft, for example, as found on most of the Continental Shelf of the United States, but collateral devices may be used to assist in the insertion of the lower end of the arm means underneath a vessel. One such assistance device may be in the form of a jetting system for supplying a waterjet through a conduit 32 so as to assist in the movement of the arm through mud or other soft bottom conwheels operated by remote control to set up a frequency of vibration atthe lowermost ends of the arms 14. The jetting devices 32 and vibrators 34 may be used separately or in combination with one another, depending upon the bottom conditions encountered during a salvaging operation. Electric m'otors, hydrazine turbines, or other devices may be carried in the legs to operate pumping functions for the water jet system and vibrating functions for the vibrating systems.

FIG. 9 illustrates a detail of a depending leg member 28 connected to the upper structure 12 of the support frame means 10. Each leg member 28 is rigidly affixed to the support frame structure and is reinforced to support and carry a pontoon means 24 associated with a plurality of such leg members along one side of the support frame structure. In addition, each leg member may be provided with track elements 36 for receiving the structures 30 carried by the pontoon means 24. In the illustrated embodiment, four dependingleg members are provided on each side of the support frame structure 10 so as to define two parallel rows of legs which can receive and carry the two separate pontoon means 24on each side of the salvage unit. The leg members 28 may be of a hollow construction so that they can contribute to additional buoyancy for the support frame, and each leg may include an interior space which communicates with at least one compartment of the upper support frame structure. Also, conventional jacking mechanisms may be included in the leg structures for jacking the pontoons up and down the legs. Such jacking devices are of a well-known construction and are typically used for offshore drilling platform structures.

As mentioned above, another problem with prior designs for salvage units resides in a-lack of control to maintain a sta ble attitude of the unit and of a contained vessel once the vessel is initially lifted'away from the bottom of a body of water. Buoyancy must be carefully controlled to avoid an extremely rapid rate of lift of the vessel to the surface, and there is always a danger of the entire system overturning if buoyancies cannot be carefully set and balanced on all sides of the salvage unit and its retained vessel. The present invention overcomes the problems of buoyancy and balance by providing a novel buoyancy compensator means. The buoyancy compensators may be provided in the support frame tanks and in each of the pontoon means 24. FIGS. 10 through 13 illustrate details of a buoyancy compensator 40 in accordance with this invention, and FIG. 6 illustrates placement positions for a plurality of such buoyancy compensators in each pontoon means 24 so that each compartment a through c of a single pontoon means can be controlled as to its positive or negative buoyancy. As shown in FIG. 10, each buoyancy compensator 40 comprises a tubular member which communicates between'an outside en-. vironment (the sea) and the sealed interior space of a pontoon means (or of a single compartment within a compartmented pontoon or tank). The lowermost end 42 of the buoyancy compensator 40 is adjusted in its vertical level within the compartment space which is to be controlled, and water can be received through the hollow tubular structure of the buoyancy compensator. When air, or other buoyancy gas, is introduced into the same compartment space, water will be displaced outwardly through the buoyancy compensator once the pressure of the air or gas has equalized with the water pressure within the compartment. However, when the water level reaches the lowermost end 42 of the buoyancy compensator, the air or gas will be allowed to escape through the exposed open end 42 and no further water will be displaced from the compartment irrespective of the pressure of the compressed air or gas. Thus, the level at which the lowermost end 42 is extended into the compartment which is to be controlled determines the amount of water which will be left in the compartment when air or gas is introduced into the compartment. This provides for an automatic regulation of buoyancy conditions for each compartment by computing the amount of positive buoyancy which is required and by setting the buoyancy compensator to provide for that amount of positive buoyancy when air or gas is introduced. The buoyancy of a given compartment or pontoon is adjusted by lifting or lowering the open end 42 of the compensator to a level which corresponds to the desired relationship of watervolume and gas volume required for a particular buoyancy. To provide for such a lifting and lowering adjust ment of the buoyancy compensator 40, a single tubular member may extend downwardly into a compartment, and means may be provided for lifting and lowering the single tubular member. However, a preferred arrangement is illustrated in FIG. wherein the buoyancy compensator is made up of telescoping tubular elements which can be extended and retracted relative to one another to provide the desired adjustment. As illustrated, a smaller diameter tubular member 44 can be retracted into a larger diameter member 46, and a sealed relationship is provided between the two tubular members. Thus, a lifting or lowering of the element 44 results in an adjustment of position for the open end 42 of element 44. A power operated means 48 may be provided for lifting and lowering the tubular element 44, and FIG. 10 illustrates a hydraulically controlled system for effecting rapid vertical movements of the buoyancy compensator. As illustrated, the system provides for an admission of hydraulic fluid under pressure to one side or the other of a piston 50 fitted within a cylinder 52. Known and conventional control and pumping devices may be provided for pumping hydraulic fluid from surface support vessels into either conduit 54 or 56 to effect a lifting or lowering, respectively, of the tubular duct element 44. Alternatively, it may be desirable to utilize divers to manually adjust the positions of the compensators at underwater levels.

'Movements of the piston 50 are transmitted by a rod 58 to a bracket 60 affixed to the tubular duct element 44. Another advantage in providing a power system .48 to adjust the buoyancy compensator 40 is that the compensator can be moved very rapidly upwardly with a power system to quickly vent a compartment or tank, if required. For example, if extremely unstable conditions are developing during the lifting of a sunken vessel towards the surface, such as an extreme tendency for the entire salvage unit and its contained vessel to overturn, it is possible to rapidly vent pontoons or tanks on one side (or to vent all tanks simultaneously) by rapidly lifting the buoyancy compensators to vent compressed air from the tanks and to admit water into them. In the illustrated embodiment, the tubular buoyancy compensator 40 extends upwardly through an upper deck of a pontoon 24, and a screen 62 may be provided to prevent the admission of foreign matter into the pontoon. Of course, it will be appreciated that the described buoyancy compensator can be of any desired cross-sectional configuration, and the compensator can be used forany tank, pontoon, or compartment for which a buoyancy control is desired.

By using a plurality of buoyancy compensators 40 in combination with separate compartments of the two pontoon means 24, it is possible to carefully control the buoyancy of the salvage unit to match the weight curve of a sunken vessel, and previously calculated positive buoyancies can be set for all of the pontoons and compartments so that the admission of gas into the compartment automatically provides a desired buoyancy effect for the particularjob at hand. In practice, the

total buoyancy of the two pontoon means 24 is set to substantially match the load weight and distribution of weight of the sunken vessel which is to be lifted. However, this buoyancy is not sufficient to lift the combined weight of both the sunken vessel and the salvage unit itself, and therefore, actual lifting of the vessel does not begin until buoyancy tanks associated with the support frame at 12 are adjusted in their buoyancies.

In this sense the buoyancy of the support frame 10 is used to control the sinking and lifting of the entire unit, while the buoyancies of the pontoons is used to match the system to the load which is to be lifted. Thus, the pontoon means 24 can be filled with compressed gas to displace known quantities of liquid as soon as the grasping arms 14 are in position, and there is no danger ofa premature lifting or floating of the sunken vessel.

Although each buoyancy compensator 40 may be provided with an open end 42 with no additional structures or devices, a stabilizer valve means 70 may be utilized for purposes of providing additional features of balance and control. It has been found that the two pontoon means (or whatever number are being used in a given structure) on opposite sides of a salvage unit can be regulated relative to one another to maintain a balance which will assist in keeping the salvage unit and its retained vessel in a preferred upright attitude. Each stabilizer valve means (FIGS. l0, l2 and 13) comprises a valve plate member 72 (a butterfly valve type of known construction is suitable) which is actuated about a pivotal axis 74 by floats 76. The floats 76 are rigidly connected to the valve plate 74 through a bracket structure 78 in such a way that movements ofthe bracket will directly rock the valve plate 72 about its axis 74 on a pin 80. The valve plate" may include a slot through its central portion for receiving a projecting portion of the bracket 78, and the projecting portion of the bracket may be pinned in place relative to the valve plate, so as to be easily disassembled or repaired. The valve plate 72 is set at an angle relative to the open end of the buoyancy compensator, as shown in FIG. 10, so that the stabilizer valve means 70 will haveno effect upon the compensator when the floats 76 are riding in a substantially horizontal plane. However, when the floats are tilted, the angle of the plate 72 will be adjusted to provide additional compensation to the buoyancy of the system. The valve plate 72 can be tilted in a clockwise direction about the axis 74 (of FIG. 10) for a sufficient distance to seal the open end 42 of the compensator. The valve plate 72 seals the open end when its peripheral surfaces engage upper and lower valve seats 82 and 84, respectively. With the stabilizer, valve means 70 which has been just described, it is possible to relate buoyancy compensators on opposite sides of the salvage unit so that a tilting'of the entire unit in one direction about the central longitudinal axis of it retained vessel will automatically provide an adjustment in opposed pontoon means to overcome the unstable condition. FIG. I4 illustrates the relationship which can be provided by the stabilizer valve means 70 when such valve means are situated in buoyancy compensators on opposite sides of the salvage unit. Considering the relationship shown in FIG. 14, the stabilizer valve means 70 of the left-hand pontoon means 24 will seal the open end of the buoyancy compensator 40 if the left pontoon means 24 tilts downwardly relative to the right pontoon means 24 along the line X-X. This prevents the escape of any air from the left-hand compartment 24, thereby maintaining its buoyancy. On the other hand, the stabilizer valve means 70 of the right-hand pontoon means 24 permits an escape of air from the pontoon during such a tilting movement, and this changes the buoyancy of the right-hand pontoon to increase its negative buoyancy. Such a change in buoyancy has the effect of righting the entire system to a more stable condition wherein the two pontoons are related to one another along a substantially horizontal plane. Without a provision for a balancing between opposite sides of the salvage unit, there would be a possibility of a lowermost pontoon losing more and more of its positive buoyancy during the tilting movement just described, and this could lead to an uncontrollable situation which would capsize the entire system.

Although the grasping arm means 14 may be of any suitable shape or configuration, it is possible to provide flexible pad structures on the inner surfaces of the separate arm means 14 so as to provide a frictional engagement of the arm means with the side walls ofa vessel being engaged by the opposite rows of arms. FIGS. 15 through 17 illustrate examples of flexible pad structures which may be provided to conform the inner configurations of the arm means to whatever shape of vessel is being encountered. Alternatively, bulkheads can be constructed and installed on the arm means to fit whatever special configuration is encountered in a salvage operation. The flexible pads 90 which are illustrated include a friction pad 92 for actually contacting a'vessel. The friction pad 92 is carried and supported by spring means 94 which are interconnected to provide a uniform pressure distribution over the entire contact area of the pad 90. Pivotal connections 96 are provided for attaching the spring means to the arm 14 and to remaining elements of the spring.

FIG. 18 illustrates a piping diagram for compressed air con trols for the salvage unit. A bundle of air supply hoses 100 connects the salvage unit to surface support vessels, and the separate hoses communicate with separate parts of the salvage unit through a distribution system made up of pipes 102. The pipes 102 are supported on the upper deck of the support frame 10, and from there a number of the pipes extend, through flexible or telescoping connections 104, to the pun toons 24. ln addition, conduits are provided for supplying hydraulic fluid to rarns connected between the pontoons and the arms of the unit, and manually operated venting valves 106 are provided. for the compartments making up the buoyancy system ofthe salvage unit.

The operation of the described salvage unit maybe in accordance with any known practices for aligning, sinking, and floating submersible devices. As an example of operation, reference is made toFlG. 1 wherein the salvage unit is shown in a floating condition adjacent to the location of a sunken vessel 200. Before salvage operations are started, a survey crew, using standard Navy procedures, determines any intact buoyancy of the sunken vessel 200, and the known weight and load of the vessel is determined from records. The sunken vessel is marked by a mooring system comprising a number of buoys 202 positioned to mark the location of the vessel. The buoys are connected to anchors 204 around the vessel by a first set of cables 206 which extend between'the anchors 204 and the buoys 202. Preferably, the buoys 202 are connected to the cables 206 so as to be quickly releasable therefrom. One method of'aligning the salvage unit with sunken vessel includes the steps of running-slack lines 210 from the buoy positions to the salvage unit floating nearby. This can be accomplished with tugs or other vessels, and then, the salvage unit can be drawn into an aligned position over the sunken vessel by tightening the lines 210. Alternatively, the salvage unit can be towed by an air supply vessel over the mooring system to receive the buoys 202 into a cage by guide runners 208 pro vided in the salvage unit (see FIGS. 5, 6 and 19). The guide runners 208 function to guide the buoys into a cage 209 so that the lines 206 and 208 can be connected together. Once the cables and buoys are guided into-the cage 209, the buoys another set of buoys 212 positioned on the upper deck of the support frame 10. Once the two sets of cables are connected to one another, there is provided a system of continuous cables from the anchors 204 to winches 214 and buoys positioned on the upper deck of the salvage unit. A hook means 211 may be carried on a portion of the pontoon 24 for temporarily receiving an end ofa cable 206 while the buoy 202 is being disconnected. The cage 209 may be of any suitable construction to receive and hold a buoy, and preferably the cage 209 is-releasably secured to a pontoon so that it can be lifted by cables when it is not needed.

Next, all buoyancy compensators of the pontoon means 24 are adjusted by the power systems 48 to match the buoyancy of the pontoon means 24 with the calculated effective weight for the sunken vessel 200. Flexible pads 90, or bulkheads, are adjusted to fit the particular vessel, and the salvage unit is in condition for sinking. During the sinking procedure, the cables 206 and 210 are maintained taut by winches 214 carried on the salvage u'nit. instead of winches, tugs may be used for hauling the cables 206 to maintain them taut. The next step of the procedure requires the placement of a crew aboard the salvage unit, and the crew floods the end tanks on each ofthe pontoon means 24. Catwalks may be provided above the deck of the pontoon means so that a crew can find easy access to the pontoons of the floating salvage-unit. Initially, the upper deck of the support frame 10 may be feet or more above the surface of the water, but a flooding of the end tanks of the pontoons will bring the upper decks of the pontoons down to the level of the surface of the water. During towing and initial sinking operations, the pontoon means 24 will be locked in their highest positions, and the arms 14 will be locked against the legs 28 in their most open positions In order to place the pontoon means 24 in their uppermost positions while, at the same time, maintaining the opposed arms14 completely open, it is necessary to fully retract the hydraulic rams 26 associated with the linking members between the arms and the pontoon means. In an alternative arrangement, jacking devices associated with the legs ofthe support frame can adjust the position of the pontoons, and telescoping members can be substituted for the hydraulic rams 26. Once the end compartments of the pontoon means 24 are flooded, the hydraulic rams 26 are extended so as to place the pontoon means 24 at their lowermost positions on the legs 28. Initial placement of the pontoon means 24 at their uppermost positions is done only to strengthen the entire salvage unit while it is being towed to a work site and aligned for sinking.

Once the pontoon means are flooded and moved down to the surface of the water, the crew climbs to the upper deck of the support structure 10 where valves are operated to complete the flooding of all compartments of the pontoon means 24. Then, the tanks of the support frame 10 are flooded as far'as sea conditions will permit, and the crew is removed from the salvage unit 10. Final flooding and sinking of the salvage unit 10 is accomplished by venting the tanks of the support frame structure. Venting can be accomplished by the use of compensators 40in the support frame tanks, such compensators being of the same general construction as discussed above. The compensators may be provided with valves, if

desired, for operation from a remote location.

Once the unit is on the bottom, all air in the support frame is vented so that the weight of the entire unit can be used to'sink the unit into a grasping position. When the unit isin a proper position for grasping the sunken vessel, the water jets are operated to assist in a placement of the arms under the vessel. Then, air is pumped into the pontoon means 24, causing them to lift on their associated legs 28, thereby causing the arms 14 to move into grasping positions around the sunken vessel.

Since the buoyancy compensators for the pontoon means have been set to match the weight of the vessel, but not combined weight of the vessel and the salvage unit, addition of air into the pontoon functions to move the arms 14 into grasping positions without any danger of a premature lifting or floating of the complete system. if necessary, vibrators and the water jets can be used to assist in the movement of the arm means 14 into engagement with the sunken vessel.

Once the sunken vessel is fully retained by the two rows of arms 14, the support frame structure is filled with sufficient air or gas to'adjust its buoyancy to lift both the salvage unit and the retained vessel. It sufficient buoyancy cannot be obtained this way, the buoyancy compensators of the pontoon means can be further adjusted (by remote control, by submersibles, or by divers) to provide additional buoyancy. As the salvage unit begins to lift the vessel, buoyancy on opposite sides of the salvage unit will be adjusted by the stabilizer valving means 70 discussed above if an offcenter load is encountered. However, should the salvage unit begin to slip off from the vessel, or if any other complication arises, buoyancy can be quickly relieved by actuating an emergency release switch which causes a simultaneous operation of all compensators to vent air from the pontoon means 24.

Once the salvage unit and vessel have surfaced, air lines or hydraulic lines are connected to the hydraulic rams 26 to force the pontoon means 24 downwardly on their legs 28. Alternatively, jacking means can be used for moving the pontoons relative to the support frame. The pontoon means 24 are moved downwardly for a sufficient distance to lift the freeboard deck, or other structure, of the vessel above the surface of the water. Then, the vessel can be made seaworthy by the use of floatation bags, foam, or any known method or combination of methods for adding buoyancy to a vessel.

Thus, it can be seen that this invention provides for substantially improved features of performance and safety. A sunken vessel can be grasped and lifted to the surface in a controlled operation, and once near the surface, it can be floated and released from the salvage unit, if desired. The salvage unit can continue operations in a given area to lift additional vessels or objects, or it can be floated to another location with a raised vessel retained within its grasp. Ofcourse, the salvage unit can be used in various depths of water even though it is especially useful in deep water operations. The salvage unit which has been described is manufactured and assembled in accordance with known ship building techniques. It may be manufactured from metal plate of suitable thickness, and various parts may be welded. or otherwise secured together, to produce an integral, complete assembly.- if desired, the salvage unit can be provided with propulsion devices to make it self-propelling.

Although the invention has been described with reference to a particular embodiment, it will be understood that variations in the described embodiment will become obvious to those skilled in this art. Also, certain modifications or additions can be made to the described structure. All obvious variations and modifications are intended to be included within the scope of this invention.

We claim:

1. A submersible salvage unit which can be sunk in deep water to receive and lift a sunken vessel or other object to the surface, comprising:

A support frame means for carrying arm means which can be actuated to contact and engage the sunken vessel, said support frame means having downwardly depending leg members for supporting pontoon means which can be vertically adjusted relative to said leg members of the support frame means; and

a plurality of arm means connected to said support frame means with at least a number of said arm means being positioned and connected for movement towards and away from the remainder of the arm means so that the plurality of arm means can be placed over a sunken vessel and moved into a grasping contact with the sunken vessel forengaging and'holding the sunken vessel while it is being lifted to the surface ofa body of water, and at least said number of said arm means being operatively connected to said pontoon means so that the arm means can be moved towards and away from a sunken vessel by adjusting the positions of said pontoon means relative to said support frame means.

2. The salvage unit of claim 1 wherein said support frame means is of a sufficient length and width to carry said plurality of arm means substantially within its confines, said plurality of arm means being arranged so that downwardly depending portions of the arm means are arranged in two rows within said support frame means to define a space into which a sunken vessel can be received.

3. The salv age'unit ofclaim 2 wherein individual arm means are pivotally connected to said support frame means so that the two rows of downwardly depending portions of the arm means can be moved towards and away from each other in response to lifting and lowering movements of said pontoon means associated with the arm means.

4. The salvage unit of claim 3 wherein each of the arm means is operatively connected to a pontoon means through linking members which transmit up and down movements of the pontoons to laterally extending portions of the arm means so as to rock each arm means about its pivotal connection to said support frame means, thereby translating vertical movements of said pontoons into transverse movements of the downwardly depending portions of said arm means.

5. The salvage unit of claim 3 wherein each arm means comprises a member having (a) a downwardly depending portion which extends downwardly within the confines of said support frame means on one side of the pivotal connection of the arm means to the support frame means and (b) a laterally extending portion which extends laterally outwardly of the support frame means on an opposite side of said pivotal connection, and each arm means being actuated by a pontoon means which is on an opposite side of the unit from the row in which the depending portion of the arm means is positioned, with pairs of such arm means being arranged to oppose each other in their placement and actuation within the support frame means.

6. The salvage unit of claim 4 wherein said linking members between the pontoon means and the arm means includes extensible portions which can be operated to move the pontoon means relative to the support frame without causing an adjustment in position of said arm means.

7. The salvage unit of claim 2 wherein said pontoon means can be adjusted in their buoyancies by buoyancy compensators which each comprise a tubular memberhaving an open end extending downwardly into the interior of a pontoon means so as to allow the passage of water into and out of the pontoon means, and means for introducing air or gas into the pontoon means for displacing water therefrom only to a level which is at the lowermost open end of the compensator, thereby regulating the volume of water which remains in the interior space or compartment within the pontoon means, and including means for adjusting the vertical position of the lowermost open end of the compensator, whereby buoyancy of a pontoon means is adjusted by adjusting the distance at which a compensator extends downwardly into the pontoon means.

8. The salvage unit of claim 7 wherein each buoyancy compensator includes power operated means for extending and retracting-the lowermost end of the compensator relative to the interior space of a pontoon, and including means for rapidly retracting the lowermost end of the buoyancy compensator in an upward direction to permit a rapid release of gas from the pontoon.

9. The salvage unit of claim 7 wherein buoyancy compensators are included in pontoon means on opposite sides of the salvage unit so that opposed buoyancy compensators can function to maintain a stable balance of the unit in water, and including valve means in each buoyancy compensator for adjusting the buoyancy of one or more opposed pontoon means to compensate for an unstable attitude of the salvage unit.

10. The salvage unit of claim 9 wherein each valve means comprises a valve plate means actuated by a float so as to close the tubular member of the buoyancy compensator when the pontoon means, in which the buoyancy compensator is positioned, is tilted into an unstable condition.

11. The salvage unit of claim 10 wherein buoyancy compensators in opposed pontoon means open and close their associated tubular members in opposition to one another, whereby a buoyancy compensator on one side of the unit is sealed by its valve plate means at the same time that a buoyancy compensator on an opposite side of the unit is opened by its valve plate means when the salvage unit is tilted in an unstable attitude.

12. The salvage unit of claim 1 wherein each arm means includes a projecting lowermost end portion which can be inserted underneath a sunken vessel when the arm means is brought into engagement with the vessel for lifting the same.

13. The salvage unit ofclaim 12 wherein the lowermost end portions ofthe arm means include jetting devices for assisting in an insertion of the arm means underneath a sunken vessel.

14. The salvage unit of claim 1 wherein said support frame means includes a buoyancy tank for assisting in the lifting of the combined load ofthe sunken vessel and the salvage unit.

15. The salvage unit of wherein each arm means carries a flexible'pad means for frictionally engaging the walls of a vessel which is contacted by the arm means.

16. A method for engaging and lifting a sunken vessel, or other object, with a salvage unit comprising the steps of:

marking the sunken vessel with a number of buoys, with buoys being placed at each side of the vessel position, by placing anchors on each side of the vessel and connecting a first set of cables between the anchors and the buoys;

towing a floating salvage unit to the vicinity of the buoys marking the position of the sunken vessel;

connecting lines between the salvage unit and the buoys so as to align the first set of cables with a corresponding set of cables carried by the salvage unit;

releasing said buoys;

maintaining the two sets of cables taut while sinking the salvage unit over the sunken vessel;

sinking the salvage unit over the sunken vessel by adjusting the buoyancy of the salvage unit;

grasping the sunken vessel with arm members of the salvage unit which are connected to pontoons carried by the salvage unit, said grasping step being carried out by adjusting buoyancies of the'salvage unit so as to move said pontoons relative to a support frame which carries opposed pairs of the arm members, thereby moving opposed pairs of arm members into engagement with opposite sides of the sunken vessel; and

lifting the sunken vessel by increasing the buoyancy of the salvage unit.

17. The method of claim 16, and including the additional steps of adjusting the total positive buoyancy capabilities of said pontoons to substantially match the calculated or known weight of the sunken vessel, whereby an introduction of gas into all of the pontoons will effect a grasping movement of the arm members around the vessel but will not lift the combined weight of the sunken vessel and the salvage unit and lifting the combined weight of the sunken vessel and the salvage unit by introducing a gas into tanks carried by said salvage unit.

18; The method of claim 16 and including the steps of: maintaining the arm members in a grasping position about the vessel after the salvage unit is lifted to the surface; and

moving the pontoons downwardly relative to the retained vessel without adjusting the positions of the arm members which are connected to the pontoons, whereby theupper structure of the vessel is brought to the surface.

19. The method of claim 16 wherein said salvage unit is aligned with the sunken vessel by receiving said buoys into guide runners carried by the salvage unit so as to align the first set of cables with a corresponding set of cables carried by the salvage unit. 

